Which of the following factors helps explain the rise of urban centers and the increase in trade in Afro-Eurasia during the second half of the thirteenth century? A.)
The increase in all forms of coerced labor to build housing
B.)
The decline of the Mongol khanates across Asia
C.)
The reopening of Indian Ocean trade networks by Chinese explorers
D.)
The availability of safe and reliable transport along land-based trade routes

D. The availability of safe and reliable transport along land-based trade routes.

Explanation:    

The Afro- Eurasia, saw the rise of urban centres and trade during the half of the 13th century because of the trade routes. Trade routes like the silk road play a fundamental role in Afro- Eurasia regions. The Silk Route is one of the oldest land routes that linked China to the Mediterranean region and other countries like India and the Middle East for trade. Materials from Asia known for its quality and luxury as is consumed by wealthy people in Europe. Some of the goods that traded were silk, tea, sugar, porcelain, spices, and cotton. The urban centres developed with the prosperity of growing trade.  

the answer is 1.. i think